So I have an 04 400ex and I just recently bought a Big Gun Evo. I also got an FMF power up jet kit. I talked to the people at Big Gun and they said the main jet is the only thing I need to change. (180-200) does anyone know what jet I use in the FMF kit?
42 pilot jet. I would use the needle out of the fmf kit if there is an adjustable one. Go one clip down(pointed end being bottom) from the middle slot. And a 160-165 main jet. You will have to remove the carb from the quad entirely. Take the float bowl off and change the pilot jet. It will have a flat tip head on it. Under a little plastic baffle. The 42 pilot jet will make the quad start up alot better when cold. While you have the bowl off change the main jet. It will be sticking out further then the pilot jet and be a hex headed jet. Then put the bowl back on and remove the top to get at the needle. Since your quad is an 04 your stock needle may already be adjustable. If it is just drop the clip on slot. If not use the fmf kit needle that should be adjustable. To get the needle out you gotta remove the 2 phillips screws down in the slide. They will be a real pain to put back in without a magnetic tip driver. You also have to remove the bigger phillips screw and swing the whole thing out of the way. Getting the bigger screw back lined up with the shaft can be alittle bit of a pain also. Good luck and ask alot of questions if you get stumped.
The 42 pilot jet is just advised. Not 100% necessary but the quad will run alot better with it. They come so lean from the factory for emission regulations that any modification at all requires more fuel in all places. I would if your not going to up the pilot turn the mixture screw out about a full turn. That will compensate some but the 42 would be better. Btw i know your new here but we try to keep a family friendly forum here. We will edit your language from time to time. But if it gets excessive we will take action. Like i said though your new and i completely understand because most forums are not like this one. Any other questions feel free to ask away!
Ask as many questions as you need! Thats why we are all here. When you are tuned spot on you will start easy first or second try and idle nice and smooth. It will rev clean and respond fast. You will have no popping or flame out on decel and the motor will not get excessivly hot. You should notice no bogging or flat spots in the power curve.